St. Therese de Lisieux
The 8-year-old French saint
was so clever she found herself in a class for 14-year-olds -- although she still struggled with math and spelling. This actually created envy among her peers, and she described these school years as the "saddest" of her life. She spent the following years determined to enter the Carmelites, even beseeching Pope Leo XIII's intervention. Finally, at 15, she entered the convent in Lisieux with her father's blessing.